1. Field of the Invention
The present invention relates generally to the field of di(hydroxyphenyl) monomers and more particularly to di(hydroxyphenyl)-1,2,4-triazole monomers.
2. Description of the Prior Art
Poly(1,2,4-triazoles) (PT) are heterocyclic polymers which were first synthesized by the reaction of bistetrazole monomers and a bisimidoyl chloride monomer. [C. J. Abshire and C. S. Marvel, Makromolecular Chemistry, 44/46,388 (1961)]. Since then several different reaction pathways have been developed to prepare these polymers. The next method of preparing PT involves reacting a polyhydrazide with aniline. This reaction when carried out in polyphosphoric acid at approximately 175.degree. C. produces PT of high molecular weight. [J. R. Holsten and M. R. Lilyquist, Polymer Science, A, 3, 3905 (1965)]. Another synthesis of PT involves reacting a bisamidrizone (also referred to as a bishydrazidine) monomer at low temperatures with a diacid chloride monomer. The resulting precursor polymer (poly N-acylamidrazone) is then cyclized either to the poly(1,2,4-triazole) or the poly(1,2,4-oxidiazole), depending on the reaction conditions. The poly(1,2,4-triazoles) prepared by this route have been shown to contain approximately 4% oxidiazole and uncyclized amidrazone along the backbone. [M. Saga and T. Shono, Journal of Polymer Science, B, 4, 869 (1966). Also, V. V. Korshak, "Heat Resistant Polymers" Israeli Translation, Keter Press Jerusalem, 1971, p. 244-248. See also P. M. Hergenrother, Macromolecules, 3(1), 10 (1970)]. The last method for preparing PT involves reaction of a dinitrile compound and bisnitrilimine. This route, however, yields only low molecular weight polymer. [J. K. Stille and F. W. Harris, Journal of Polymer Science, A-1, 6, 2317 (1968). Also, J. K. Stille and L. D. Gotter, Journal of Polymer Science, A-1, 7, 2492 (1969)]. For a general review of PT see "Thermally Stable Polymers" by P. E. Cassidy, Marcel Dekker, Inc. New York, p. 203.